Buying a diamond is something most people do very rarely, but it’s usually a considerable and exciting investment, so let me give you some pointers on the main factors determining the cost and value of a diamond.

The most important things to look for are known as the 4 Cs: Carat, Cut, Clarity and Color.

Before you buy a diamond, there are a number of things you can do to make sure that you are roughly able to assess the quality of the diamond yourself. Although it takes years to become a real expert, if you read up and educate yourself before you go shopping, you are far less likely to pay too much for your diamond engagement ring.

Carats are the units of weight used for diamonds. Each carat is divided into 100 points. 1 Carat equals 1/5 gram. Remember that a carat is weight, not size and that a well-cut diamond may appear larger than a badly cut diamond of equal weight.

Color is graded from "D to Z". A diamond graded as "D" will be colorless, the most desirable and the most expensive. However, the difference between it and a stone graded "E" is not noticeable to the non-expert and even an expert needs a comparison stone to see the difference. Once a diamond is mounted in a ring it is generally almost impossible to tell the minute color grade differences.

We find that the acceptable range for "ring quality" diamonds is a stone that rates anywhere from "D" color through "J" color. There are very good values to be had on a diamond below a "J" color, however you will start to pick up a more noticeable tint of color. At the bottom end of the scale a "Z" diamond would be have a strong yellow tint (or whatever body color the diamond has).

Very occasionally diamonds are found with a strong natural color to them and are graded in as a Fancy Light, Fancy, Fancy Intense, or Vivid (which is the most rare). In some instances, these stones can command huge premiums but natural colored diamonds are available in all shapes, sizes, and price ranges.

Cut is where the skill of the diamond cutter creates the maximum shine and sparkle from the rough stone. For many centuries the priority was to get the largest possible gem that could be cut from the rough. Nowadays, while still hoping not to waste precious material, the cutter is more likely to go for maximum brilliance. This is achieved by cutting the diamond so that light entering it is reflected back to the beholder.

The better the cut the more light reflected. A well cut diamond is worth far more than a badly cut stone of equal weight. Shape is also an aspect of cut with the most fashionable shapes, currently round and square, commanding a premium over less pop ones.

Clarity denotes the number of flaws in a diamond. These are formed as the diamond is being created the Earths core. Internal flaws are known as inclusions, external ones as blemishes. A jeweler will look for flaws with a loupe. He will note every flaw and grade the stone accordingly.

We find the most acceptable clarity range for a "ring quality" diamond is from VVS to SI range. Stones in the Imperfect range, although widely used for engagement rings, will have eye visible inclusions without the aid of any magnification. These stones will represent a good value for those not as worried about overall quality.

One other element which can affect the value of a diamond is fluorescence, which is the way a diamond “soaks up” light. Diamonds are graded None to Strong for fluorescence, with those with a high level considered less desirable and thus cheaper.

Most of the above aspects of diamonds you will be able to assess at a basic level with some education and the help of our knowledgeable staff here at August Stephenson.